I've always thought Elijah was too young for Frodo. Frodo got the ring when he was 33, and left the shire at age fifty. Factoring in the effects of the ring, and differences between hobbits and humans, I figured a 35 year old actor would be most appropriate.

For Bilbo... he was fifty, but no ring, so... (sigh) yeah, I guess Ian Holm IS too old. I just hope they don't go too young. There's a lot of natural comedy in the hobbit because Bilbo is an overweight, middle-aged guy being thrown into an adventure he's not ready for. I like all the actors people are buzzing about, especially Martin Freeman, but I think maybe they're just too young...